Improving the photovoltaic properties of GaAs/GaAsBi pin diodes by inserting a compositionally graded layer at the hetero-interface
Improving the photovoltaic properties of GaAs/GaAsBi pin diodes by inserting a compositionally graded layer at the hetero-interface
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DOI：
10.1088/1361-6641/ac66fa
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发表时间：
2022-06-01
影响因子：
1.9
通讯作者：
Yoshimoto, Masahiro
中科院分区：
文献类型：
--
作者：
Kawata, Hiromu;Hasegawa, Sho;Yoshimoto, Masahiro
研究了在GaAsBi/GaAs界面处插入成分梯度层对GaAsBiPin二极管的光伏和发光特性的影响。当PIN二极管作为太阳能电池运行时，插入渐变层可将开路带隙电压偏移(W(Oc))提高到0.51V，这与预计将用于多结太阳能电池的其他材料(如带隙为1.0 eV的GaInNAs(Sb))相当或更好。相比之下，对于没有渐变层的PIN二极管，W(Oc)可以高达0.71V。当它作为发光二极管工作时，在这种二极管中插入渐变层可根据其电致发光强度将非辐射复合抑制1/50倍。插入梯度层还可以避免发生从非金属性质的GaAs向金属性质的GaAsBi转变的特殊的异质界面的劣化。此外，在生长GaAsBi层之前，当生长中断时，梯度层在低温下有效地避免了界面处的氧堆积。因此，插入梯度层是提高含GaAsBi少数载流子器件性能的关键。
We investigated the effect of inserting a compositionally graded layer at the GaAsBi/GaAs interface on the photovoltaic and light-emission properties of GaAs/GaAsBi pin diodes. When the pin diode is operated as a solar cell, inserting a graded layer improves the open-circuit bandgap-voltage offset (W (oc)) to 0.51 V. This is comparable to or better than other materials-such as GaInNAs(Sb), which has a bandgap of 1.0 eV-that are expected to be used in multijunction solar cells. In contrast, W (oc) can be as large as 0.71 V for a pin diode without a graded layer. When it is operated as a light-emitting diode, inserting a graded layer in such a diode suppresses nonradiative recombination by a factor of 1/50 based on its electroluminescence intensity. Inserting a graded layer also makes it possible to avoid deterioration of the peculiar hetero-interface where the transition from the non-metallic nature of GaAs to the metallic nature of GaAsBi occurs. Moreover, the graded layer is effective in avoiding a pile-up of oxygen at the interface at low temperatures when growth is interrupted just before growing the GaAsBi layer. Thus, inserting a graded layer is the key to improving the performance of minority-carrier devices containing GaAsBi.